A typical fire detector may include a smoke detector, smoke gas detectors, or smoke alarms. Some detectors may be referred to as point detectors or as point-type detectors. These types of fire detector typically have a detection unit operating in accordance with the scattered light principle for detection of smoke particles. As an alternative or in addition they can have a gas sensor for detecting gases typical of a fire. Furthermore such fire detectors may include a temperature sensor for detection of an impermissibly high temperature in their environment.
Furthermore the fire detectors may be connected via a common detection line, in particular via a two-wire line, to a fire alarm center for signaling and/or data transmission. They can also have an autonomous energy supply, such as a battery. Furthermore the fire detector can have a radio module for transmitting an alarm message, a warning message, or status information to a neighboring fire detector or to a fire alarm center. They can also forward an alarm message, warning message, or status information transmitted by radio from a neighboring fire detector to a further neighboring fire detector or to a fire alarm center.
According to Standard DIN 14676 “Smoke alarm devices for use in residential buildings, apartments and rooms with similar purposes—Installation, use and maintenance” said devices are to be checked at least once a year using a prescribed visual and function test. This can also be done automatically. The object of the testing is to check that on the one hand there are no disruptive objects in the environment of the smoke alarm device, such as e.g. in a circular area of half a meter around the smoke alarm device, which could cause the flow of the smoke to be detected in the event of a fire to be screened off. On the other hand the smoke inlet openings in the housing are to be regularly tested for their ability to allow smoke or smoke gas to pass through them.